Scott Dunlap's blog of trail running, ultrarunning, triathlon, and other life adventures. I enjoy the physical, emotional, and spiritual journey of outdoor events and the chance to meet cool people. This blog contains interviews, research, original fiction, new product ideas, and all things trail running.

Monday, February 05, 2007

My VO2 Max Test Results

My parents-in-law gave me a great gift for the holiday season this year - a gift certificate for a full VO2 Max and resting metabolism test. Last week I went to BaySport of Redwood City, CA, where Physical Therapist Brian Tomason put me through two sessions of testing to find out how my body utilized oxygen, fat, and calories. Both sessions used a system by New Leaf which tracked my oxygen and CO2 usage through a mask, and my heart rate. Brian doesn't get many ultrarunners, so he was excited to see what my "abnormally high levels of racing" might yield.

I've never really done much benchmarking of my heart rate (HR) zones prior to this, aside from the standard "220 beats minus your age" kind of thing. 90% of my runs are really for fun, loosely organized around a "long fartlek" or "go until it hurts". But now that Sophie is around, I've felt the need to make my ever-disappearing training time as efficient as possible. I figured a good starting point would be to make sure my training HR zones are correct. I know can hold 158 beats/minute through a 10k and it feels hard, so I figured that was roughly what my anaerobic threshold (AT) was (AT is when you start building lactic acid, and you're burning almost all energy from glycogen instead of fat - read: unsustainable for long periods of time). I do most of my aerobic training between 130 and 145 beats/minute, which feels easy to me, but just enough where I can feel my breathing pick up.

The VO2 Max Test------------------------

(Example of a New Leaf VO2 Max test with mask)

The first test was the V02 Max test. For this, they strapped on the mask and an HR monitor, and put me on a treadmill. Over the course of 25 minutes, they slowly cranked up the speed and incline until I maxed out at 12 degrees and 10 miles/hour (and nearly passed out). This calculated the oxygen and CO2 levels at each heart rate. Brian used other systems to find my body fat %, etc. Here are the test results:

MaX HR: 172. I guess that's not bad. It sure felt like the "max"!

VO2 Max: 73.3. The VO2 Max represents your peak oxygen uptake, ie, your ability to deliver oxygen to your muscles. Brian said that anything over 60 is considered "above average shape", and that most people come in around 40. A professional athlete that is tapered would come in around 80-90. Overall, it looks like my body is utilizing oxygen well, but there may be some room to grow.

Calorie Burn in Aerobic Zone: 13.1 kCal/minute from fat. Brian said this is a very high rate for use of fat calories, but he's not surprised given the volume of training and racing. Basically, I've tuned my body to burn fat very efficiently when I'm at an aerobic pace.

Anaerobic Threshold: 125 beats/minute. This is the point where your body starts needing to use glycogen instead of fat to process calories. I was very surprised to see how low this was, particularly given that I have run 50-milers with an average heart rate of 145 beats/minute. If this test was right, I haven't been doing any true aerobic training since my heart rate is too high on my "easy" runs. Close examination of the output chart shows that I am very efficient at burning fat below 110 beats/minute, but it drops off like a cliff between 110 and 140 beats/minute. A better trained athlete would have this holding steady of decreasing gradually to an AT much closer to my Max HR.

The next morning, I came in for a resting metabolism test to determine what my caloric burn needs are at rest. I had fasted for 12 hours, and they strapped the mask on me again and had me chill out in a dark room for 20 minutes to relax as much as possible. That is, as much as one can with a big tube strapped across your mouth. ;-)

The results of this test were also very interesting:

Resting heart rate: 38 beats/minute. Most of the men in my family have a low heart rate and I'm fairly well conditioned, so I'm not surprised this is low. I know individuals with resting heart rates as low as 32-34 beats/minute.

Resting metabolism caloric burn: 516 calories. This means that I only need 516 calories per day to maintain my body weight, or 744 calories on a typical non-workout day. What?!? That's like two donuts!!! A typical BMI would say that 2200 calories is about right for my age, and a standard chart prediction for a trained athlete would have been closer to 1700 calories. Brian was a bit baffled at the low reading, but then pointed out that nearly all of those calories were consumed from fat and both my oxygen and CO2 levels were shallow. Basically, my body is insanely efficient at rest. Apparently I could fast for a week on the couch and only lose one pound.

Recommendations----------------------

Brian said that I'm basically in really good shape, and that the post-test recommendations are mostly for people trying to get in shape, not crazy endurance people like ultrarunners. But he did say this:

1) My body fat level is just fine. Given my ability to stick to high levels of training, he said I could certainly get down to the 9-10% found in most elite 10k runners (ab cover shoot, anyone?). But when he saw the 100k's and 100-miler on the schedule combined with my fat-burning aerobic capacity, he suggested it would be good to carry an extra couple of pounds for fuel. He also warned that since my resting metabolism is so low, it's hard to lose weight via diet, and the only outlet would be to exercise even more than I already do.

2) I should consider "aerobic intervals" to raise my AT. Brian was a bit perplexed by my low AT calculation (given my race pace at previous 50-milers, which would have had my bonked or dead by mile 30), and warned that the test could have been off. But the quick drop off from aerobic to anaerobic indicates that I could benefit from much slower workouts just under my AT. He suggested going 5 minutes just under AT, resting for 15 seconds, then repeating over an hour.

3) I should do more weight training. Brian congratulated me on being efficient with what I have - by his calculations, my body is very good at using every muscle and every gram of fat. But that means I'm "always at 11", requiring me to recruit all that I have for every race. Weight training could give me more muscle mass, and require me to recruit less muscles for the same amount of work. I certainly have enough headroom in my resting metabolism to feed a few more muscles.

I'm going to take Brian's advice on a few fronts, and do more weight training and at least one weekly aerobic interval. I did one aerobic run this weekend at 120 beats/minute, and it was excrutiatingly slow. But there could be benefit, so I'll stick with it. I don't want to turn my favorite daily activity into too much work, so I'm going to stick with "fun" for most runs.

It certainly is helpful to have some specific numbers associated with calorie burn during exercise, and a more realistic benchmark for my daily intake. I'm burning much more during exercise than I had thought, but am using much less outside of exercise. All of this data will be helpful in charting out a food/race plan for longer runs.

I'm open to feedback if any of you have (a) ever done anything like this, and (b) see anything crazy in my test results or recommendations.

Thanks, SD

PS - Congrats to all the racers who mastered the Woodside 50k this Sat!

22 comments:

What a great gift idea! It's always fun to have more numbers to play with. Hope that your new training efforts yeild some good results.

Oh, and I saw you saturday (at Woodside) but got nervous about saying 'hi' :) I must say, though, that it was, pretty much, the most beautiful place (it must be so wonderful to live there) that I have ever run, and I'm definitely sold on trail races now. *Hopefully* the Dec. 1st Woodside race will be my first 50k.

I got a Forerunner 305 for Christmas and have loved the GPS mapping features especially when used with MotionBased.com. I have also strapped on the heart rate monitor but was less certain how to use that information. I recently bought Joe Friel's book Total Heart Rate Training and am finding that a very useful guide to training with a heart rate monitor. You might also like checking it out especially to make sense of your recent test results.

My 120 bpm run was an hour long. I warmed up for 10 minutes, then did an interval of 5 minutes at 120 bpm, then 15 seconds rest by slowing to under 100 bpm, then again and again. I did it on the road since the trail sends my heart rate all over the place.

It ended up being about an 11:30 min/mile pace. I felt tired afterwards, so it was definitely a workout. But I'm just so used to getting my adrenaline up by going fast on a trail, I didn't know what to do with myself! This would be a good workout for a treadmill.

I've since switched the AT workout over to my stationary bike, where it's easier to stay in range. I did the same kind of workout - 100 minutes, going 5 min at 120, 15-30 seconds recovery, then repeat. I watched "The Illusionist" on Netflix. ;-)

thanks, Scott- I know what you mean about trail runs getting HR all over! Keep up the good work. I had my baody fat taken when I was running in college- underwater testing. Would like to do it again someday.....see what this nona is like now! Hugs to Sophie! (I need to post some books on myb log- yikes- she needs reading material!)

Thanks for stopping by. 58 is a great V02 Max score for an off-season athlete! Or for anyone for that matter. Brian said most people he tests are lucky to break 40.

I've have heard of others' V02 Max scores, and it doesn't sound as limiting in the ultra world as one would guess. Brian Morrison, who nearly won Western States last year, has a VO2 Max of 60. So clearly you don't need to be 80+ to race fast. 40-yr-old Jean Pommier, who is currently tearing up the Masters Ultra world (and will be in States in '07) has a VO2 Max of 80 even as a Masters athlete. One thing for sure, you can move the needle on V02 Max with the right training.

Hi Scott -- Just a word of caution as people throw around their VO2max numbers. The numbers are only meaningful if the instruments have been carefully calibrated, etc. Even the best labs in the world struggle with calibration issues from time to time; when I was in a study headed by Ben Levine (Dr. "Live High, Train Low") in Dallas, the values were off by about 5-10% for a couple of weeks until a problem was noticed. Anyway, given what I know about some other runners and their VO2maxes (e.g., my 5K PR is 15:03 and my VO2max is about 70 according to two independent labs), your reading of 73 seems rather high. Without knowing anything about your running form or the lab you went to, I wonder whether (A) the reading was skewed high because of a calibration issue or (B) you are not a particularly economical runner (i.e., you use relatively large amounts of O2 to travel a given distance), in which case that's something else you might want to work on. Don't take my armchair analysis too seriously, but that's my initial reaction.

That's good advice. The folks at BaySport said the VO2 Max rating could vary as much as 5-10 points, and that only way to know for sure was to test it a few times. I hadn't thought of calibration across machines as well. I hope to do the test again in June to see. If I'm off, I'm certainly on the high side. It probably is best to think about it as "60-70".

I just posted a link to this discussion as I just had my "lab work" done recently at our (University of Kentucky) lab. I agree that calibration is an important factor, but I'm not familiar with the New Leaf systems, so I'm not sure how often it should be calibrated.

The one thing I wanted to point out is that elite athletes rarely have VO2max values above 80 ml/kg/min and very, very few are above 90 ml/kg/min.

Notice of the names only 3 are above 80, none are above 90 and 1 is below 70!

Also, I'd be pretty suspicious about a resting metabolic level that low... it almost seems like the mask was leaking or something. That's crazy low and #'s I've never seen before. (Not that I've seen lots and lots though).

interesting your AT is so low.. seems suspect, your training HRs appear to be about right from my reading.

My max hr (by treadmill stress test) is 170-172, 10k/LT about 160, also. Last year I fried myself doing too much intensity so am experimenting with long runs under 140, find even that is painfully slow. For me 140 is about a 9:50 mile, race pace is about 6:20 for 5/10k.

In the days when I was running ultras, max hr would have been a few beats higher, and did the long training runs with a group at probably well under 140. That deliberate slowing down on the longer training runs gave me great improvements at that time (marathon from 3:06 to 2:44). I don't know I'd go as low as 120 HR though..

Greg Crowther is right about not reading too much into the V02 Max scores. He is a great example - his VO2 Max is around 70, and he can run a 2:22 marathon. I couldn't run a 2:40 to save my life if needed.

It's interesting to think that less-than-optimal form might be contributing to a higher-than-usual cardio health. It might be best for me to focus on that rather than worrying about moving the AT needle a point or two.

I read with interest your blog about your VO2max and RMR test. Well done on the VO2max test! However, I think you may havea misunderstanding about the RMR. Remember you were resting when you had that test done. So the RMR is really the number of calories you require at rest or as you sleep. Once you get out of bed you start burning more calories and require more calories put in. Since you are a trail runner, I would be willing to bet you require about 6X your RMR of calories per day!

Your RMR test needs to be readministered. There is no way someone with such a high VO2 is buning less than 600 calories per day. your VO2 guy clearly has no idea what he is doing. Low results like this are a indication that the mask did not have a good seal and not all O2 was getting to the machine.

About Me

I'm a technology entrepreneur who took up trail running and triathloning back in 2001 to get off the work treadmill and see a bit more of the outdoors. I also love to eat, so the exercise helps me justify those extra helpings. ;oP I'm always interested in learning more about trail running - please comment and link away!

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